This invention relates to an integrated circuit supporting a wireless communication protocol and providing a combined radio interface and/or a combined host interface for at least one other integrated circuit supporting a wireless communication protocol, and to devices comprising a plurality of integrated circuits, each supporting a different wireless communication protocol.
It is increasingly common for wireless communications devices to support multiple radio protocols. This increases the compatibility of a wireless communications device with other devices and can allow a single device to communicate in multiple radio jurisdictions, each of which may utilise a different radio protocol.
A variety of different approaches have been used to incorporate support for multiple radio protocols within a single device. The original approach, and still the most common, is to use an independent integrated circuit (IC) for each communication protocol, with each IC presenting its own RF and host interfaces. This approach can generally only be used in devices having host interfaces that intrinsically support multiple devices attached to a single host, such as a hub-based Universal Serial Bus (USB) interface. Otherwise, the host must support multiple independent interfaces, which are expensive in terms of cost, complexity and power consumption. For host interface protocols that only support point-to-point connections such an implementation requires a master 101, 102 for each communication IC 103, 104—as shown in the example given in FIG. 1.
External components are sometimes used to combine an interface of one IC with that of another so that two or more communications ICs can share an antenna or a host interface. FIG. 2 shows a common approach for sharing an antenna 205 between Bluetooth 201 and IEEE 802.11b/g 202 ICs. The arrangement allows simultaneous receive via a shared low noise amplifier (LNA) 203 and splitter 204, but exclusive transmission by means of switches 206. These additional components increase the cost of the device and generally adversely affect the performance of the radio communications.
More recently, there has been a trend to provide support for multiple radio protocols (such as Bluetooth and IEEE 802.11) in a communications device by combining the circuitry for each radio protocol into a single integrated circuit. This trend has been driven by a belief that integrating the transceivers of each radio protocol lowers the cost and PCB area used. However, this approach brings various drawbacks, most notably decreased radio frequency (RF) performance due to poorer isolation between the RF stages of the various protocols and reduced flexibility in terms of the choice of communication protocols a device can be configured to provide and the configuration of components such as antennas. Furthermore, a combination IC is rather more complex to design than individual ICs each configured to support a single communication protocol, so such combination ICs typically take longer to bring to market.
There is therefore a need for a new approach to supporting multiple wireless communication protocols at a device which combines the flexibility and performance advantages of using separate integrated circuits for each communication protocol with the cost and size benefits of combining communication circuitry together in a single integrated circuit.